1. Field of the Invention
The present invention relates to cutlery and more particularly but not by way of limitation to a folding blade pocketknife having an infinitely adjustable leaf spring.
2. History of the Prior Art
The standard folding blade pocketknife is provided with a leaf spring which is pinned or riveted between two handle plates. The pin or rivet mounting normally comprises a pin through the center of the spring and through one end thereof. The free end of the spring is placed in sliding contact with a cam surface associated with a pivotally mounted blade.
The blade member is connected between the handle plates at one end thereof so that when the knife is closed, the cutting edge is recessed between the handle plates.
The pivotally mounted end of the knife blade has a cam surface which is in constant sliding engagement with the free end of the leaf spring. The shape of this cam surface varies from knife to knife but it is normally of a rectangular configuration having rounded corners. The cam surface has a first flattened portion which is in engagement with the spring when the knife is open and tends to hold the blade in the open position. The opposite side of the cam surface is also flattened in order to tend to hold the blade in a closed position.
Most knives are manufactured with a rather heavy spring tension. However, the heavy spring configuration prevents many young people and ladies from being able to use a standard knife since they are either unable to open the knife or in opening the knife thumbnails are broken or damaged. One reason for manufacturing a knife with heavy spring tension is that after extended use, the cam surface becomes worn and/or the spring becomes weakened such that there is little or no spring tension to hold the blade in either the open or closed position.
One recent configuration of a pocketknife or folding blade hunting knife provides very little spring tension, but which firmly locks into the open position during use. In order to close such knives, it is required that the user depress a latch mechanism while simultaneously folding the blade into the handle. While this knife has obvious safety features, it normally requires both hands to close which is undesirable for many uses.
The pocketknife art is replete with foldable closing pocketknives having various mechanisms including removeable pins, cam locks and the like which disengage one of the spring fasteners in order to completely release the spring tension on the foldable blade so that the blade member may be removed and replaced. However, this does not solve the problem addressed by the present invention.